Yesterday we finished to implement the drivers for both the distance sensors: the infrared and the ultrasonic one. They actually work better than expected as their detection cones are a little thinner than expected.
At last, Rosewheel will come with 2 infrared sensors and 1 ultrasonic sensor. The infrared sensors will be used to detect falls and ravines whereas the ultrasonic sensor will be used to detect obstacles.
It’s not possible to link the sensors to the mainboard with a wire longer than 15cm, we will not be able to place them on the top of the handlebars to detect ravines as we previously thought. But, given the fact that the detection cone of the infrared sensor is really thinner than expected we finally conclude that we will have a sufficient range to detect ravines with sensors place on the chassis basis.
Indeed, we need a range of detection long enough as even if it could sound a bit counter-intuitive, to stop, Rosewheel needs to accelerate so that it could place back its center of gravity upright the wheels axis and then stop.
For the obstacles detection, we will use the ultrasonic sensor placed right in the middle of the chassis, with a slight upward inclination so that it doesn’t take the floor as an obstacle. As the range of detection is up to 4 meters, it will generate errors with long distance obstacles that aren’t actually on RoseWheel’s path. Thus, we have to handle only the detection of obstacles that are closer than 4 meters. We haven’t yet defined this range but we will have a clearer idea during the tests.
To be continued.
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